It is well known that nerve injury due to iatrogenesis can result in debilitating loss of function to the subject. Common causes of iatrogenic nerve injury include surgical failure, traction or pressure lesions, hematoma, or inadequate positioning of the subject (Fercan Komurcu, MD et al., 2005, Annals of Plastic Surgery, 54(2):135-139).
Iatrogenic injury to head or neck nerves can be particularly serious since the head and neck house nerves involved in important bodily functions. For example, the facial nerve is the most frequently injured nerve in the head or neck area. Most facial nerve lesions are postoperative and result in loss of facial tone, voluntary movement and emotional expression in the face. Prognosis remains poor even after the use of all available microsurgical techniques to repair the injured nerve (Doychin N. Angelov et al., 1999, European Journal of Neuroscience, Vol. II., 1369-1378).
As another example, ProNational Insurance Company, a provider of medical liability insurance, frequently sees claims alleging injury to the 11th cranial (spinal accessory) nerve associated with posterior cervical node excision. Such injury results in partial or total paralysis of the sternocleidomastoid and the upper trapezius muscles. Additional symptoms often include winging of the scapula and sagging and weakness of the shoulder. (Harvey Gass, M.D., and Lizabeth F. Brott, J.D., “Practice Protection, Claims Review. 11th Nerve Injury With Posterior Cervical Node Excision”, 2001, published at http://www.pronational.com/news/advisor/Pratpro1Q2001.htm).
Efforts have focused on repairing nerve injury. For example, U.S. Patent Publications 20050069525 and 20050107380, and U.S. Pat. No. 6,821,946 each disclose methods and/or compounds for ameliorating nerve injury. However, nerve repair often does not lead to full recovery, and prognosis is often poor (see e.g., Doychin N. Angelov et al., supra).
Others have attempted to prevent iatrogenic nerve injury by educating surgeons. For example, R. Shane Tubbs, M.S., P.A.-C., Ph.D., et al. compiled information about anatomical landmarks useful for locating nerves in the head or neck (see, e.g., R. Shane Tubbs, M.S., P.A.-C., Ph.D., et al., Neurosurgery 56[ONS Suppl 2]:ONS-256-ONS-260, 2005). However, literature can only provide generalized anatomical information. Minute anatomical differences exist between all individuals. A surgical team cannot determine a particular nerve's exact position or path in a particular individual simply by reading generalized anatomical literature.
There is thus a need for improved methods of preventing iatrogenic nerve injury, particularly in the head and neck area. In addition, there is a need for improved technology to provide a surgical team with definitive information about the location of nerves in individual subjects.